Levocetirizine dihydrochloride is the dihydrochloride salt of levocetirizine, a second-generation antihistamine and active pharmaceutical ingredient (API) used in medications to treat allergic conditions. It is effective against symptoms of allergic rhinitis (hay fever), such as sneezing, rhinorrhea, and ocular itching, as well as chronic idiopathic urticaria, relieving itching and hives. The compound acts as a selective antagonist of peripheral H1 histamine receptors, inhibiting the release of histamine and reducing allergic responses without significant central nervous system penetration, thus minimizing sedation. Supplied as a white to yellow powder or crystals with high purity (≥98% by HPLC), it serves as an intermediate in the formulation of oral tablets, solutions, and other dosage forms for once-daily administration.